|This article is about a/an Precious in GoGo Sentai Boukenger.|
- Hazard Level: 260
The Mercurius Vessel (メルクリウスの器 Merukuriusu no Utsuwa) is an artifact used by alchemists for the combination of other artifacts, most notably Precious, for the creation of another object. Sealed away within a cave typically sealed off by water, the Questers calculated the period when the water would recede enough to gain the vessel to use it for their own purpose. Although the Boukengers themselves knew that the Precious was in danger, they disregarded orders in retrieval to help Eiji defeat the remnant Ashu Ouga instead. Then, with the manipulation of the other three Negative Syndicates, the Questers gain the three Precious required to create the Ultimate Artificial Lifeform Homunculus, which they gained control of with their Quester Jet Over to easily defeat the Boukengers, betray the Negatives and begin their destruction of the world. Akashi attempts a suicide attack using SirenBuilder to stop the Homuculus, but the other Boukengers prevent him from doing so, leading to a combined assault with all mechs. Ultimately it takes Eiji's return with GoGo Voyager to lead to a combined final attack with DaiBouken, GoGo Voyager and Zubaan, destroying the monster and ultimately allowing for the Boukenger to finally kill the Questers and regain the vessel.